The airbed market has evolved over the years. Early airbeds used manual pumps that did not measure pressure. More recent airbeds have included electric blower motors that had both wired and wireless hand controls, as well as diaphragm pumps (including both single and dual output-type diaphragm pumps) with hand controls.
An example of a simple type of remote hand controls are remotes which utilize up/down buttons and which do not involve a visual display indicating pressure measurement. Additionally, for conventional remotes that do incorporate pressure displays, the display reflects a pressure reading that has typically been derived one of a few ways.
First, in a “target system,” the user inputs a target pressure and the pump inflates or deflates to that targeted static chamber pressure. During pump operation the display on the handheld remote control is either blank, blinking or shows the desired target pressure. When target pressure is achieved the pump stops operation and the static pressure of the air mattress chamber is displayed. To accomplish this, the system, for example, actuates the appropriate solenoids to expose a pressure sensor to a desired chamber in isolation and takes a static pressure reading corresponding to the desired chamber. Multiple iterations of the static pressure measurement are often needed for a particular inflation or deflation operation.
An alternative to the “target system” is a “real-time” system, for which the user activates the pump by inputting inflate/deflate commands. There is no “target” pressure. The pump operates as long as the user depresses inflate/deflate buttons. When the button is released, the static chamber pressure can be measured and displayed. The display is most frequently shown in either psi or millimeters of mercury. Further, while the pump executes the command, the display may reflect either a flowing dynamic pressure, or in some cases, something like an indicative “Sleep Number” which reflects an allowable range of possible pressures. Other graphical representations may be used as well, such as bars that light up, segments that light up, etc.
In conventional systems, a cost effective solution for accurately controlling static pressure in a multi-zone chamber system is to use a single fill and drain tube connecting each discrete zone of an air mattress to a control manifold and then to measure pressure in the manifold's common chamber using a single low-cost pressure transducer. Alternative higher cost strategies employed in conventional systems utilize a dedicated static line to each chamber and individual, more expensive, low-latency pressure transducers. These conventional systems are unable to accurately determine the actual pressure of an arbitrary chamber of the air mattress (typically several feet away) which is connected with a pneumatically variable system during inflation and deflation operations.
Conventional systems that strive to provide highly accurate pressure measurements are generally based solely on “static” measurements (i.e., measurements taken while air is not flowing at or near the respective pressure transducer(s)), which causes the systems to be slow, to require many multiple stop-and-check iterations, and to be frustrating to consumers as they can behave in a counterintuitive fashion by overshooting and/or undershooting specific target pressure levels. The iterative seeking behavior of these systems also cause them to be noisy, which is undesirable in long-term care and medical applications as well as consumer applications.